Quasi-Biennial Oscillation in Warming Climate

The Quasi-Biennial Oscillation (QBO) is the primary mode of variability of the tropical lower stratosphere. As the QBO is forced by a spectrum of waves from tropical convection as well as vertical advection, it is likely to change in a warming climate. We present here changes to the QBO from experiments with doubled and quadrupled CO2 concentrations and increased sea surface temperatures by 2 K and 4 K, respectively (Experiments 3 and 4 from the Quasi-biennial Oscillation Intercomparison (QBOi) project). We will focus here on the results from the Community Earth System Model with the 110-level Whole Atmosphere Community Climate Model (CESM1(WACCM5-110L)) and compare with results from other models participating in QBOi. We will show that there is very large spread in the prediction of QBO properties among general circulation models in a warming climate and discuss the reasons for these differences.